Drill.



' PATENTBD APP.. 7,1908. J. F. MITCHELL.

DRILL. APPLICATION FILED AUG. 2.4. 1906.

2 SHEETS-SHEET 1.

No. 883,73()Y PATLNTED APR. '7, 190g.

.J. P. MITCHELL.

DRILL.

.APPLIUATION FILED AUG. 24, 1906.

JOHN MTCTLTLL, OF TOPEKA, KANSAS.

DRILL.

Specification' of Letters Patent.

Patented April 7, 190s Application mail August 24, 190e. serial No. 331,922.

To all whom fit may concern:

Be it known that I, JOHN F. MlTonELL, a citizen of the United States, residing at the city of Topeka, ill the county ot' Shawnee and State of Kan-sas, have invented certain new and useful lmprovements in Drills, of which the following is a specification.

My invention relates to that class of drills known as rock drills; and has as its obj ect the provision of a simple and durable device for olding the drill and turning the same in its reciprocation.

My invention is particularly adapted to be used with my lluid pressure engine as disclosed in my application Serial No. 246,545, filed February 20, 1905, though it is to be understood that the present disclosure may be used with any other l'orm of engine which may be vapplied thereto.

My invention is illustratedin the accompanying drawings, in which- Figure 1 is a-sectional elevation of the upper part of lny device as applied` to a l[luid pressure engine. Fig. la is a sectional elevation of the lower part of lny device. Fig. 2 is a cross section upon the line 2 of Fig. l. Fig. 8 is a cross section on the line 3 of Flg. l. Fig. 4 is a cross section on line i--.5 of Fig. l, looking in the direction indicated by theiarrow, sllown at 4. Fig. 5 is a cross section on the line 4--5, looking in the direction indicated by the arrow., shown at 5. l Fig. 6 is a cross section taken on the line 6 of Fig. l. Fig. 7 shows the details of the parts of Figs. 4 and 5.

.Tn carrying out my invention I provide a main inclosing case o having a cylinder b therein, in which the hammer portion chere shown as a iluid pressure piston-is adapted to reciprocate. Secured within the lower end of this cylindrical tube is a metallic sleeve d into which extends an elongated v)ortion e ol the hammer c, such portion hav ing threaded within its bore a polygonal casingf formed of hard steel, adapted to engage the drill g to prevent the saine from turning and to hold it in such close communication with the hammer portion c that the impacts will be given to the drill Without loss due to friction. Threaded within the outer end ol the portion (l is the collar h forming the bearing for the sleeve i which is pro- .vided with a polygonal bore-in which the secured over the extending portion of the collar `i to hold the same in place.

In using a device of this class for drilling in rock, it is desirable that the drill be' slightly rotated at each stroke, and in order to accomplish this, the rifled guide bar r is fitted into the upper end of the hammer portion c, suchthat the oscillation ol the latter upon its upward stroke causes a rotationy of the guide bar Yr, but such that upon the downward stroke the rotation is given to the hammer portion and thereby to the drill. Upon the upper end of the guide 7c is the flange Z, provided with a rectangular lateral cavity therethrough in which are placed the two ratchet portions m adapted to be pressed into registry with :the ratchet teeth n in `the ring o by the coil spring p. It will be readily seen that the guide bar may be rotated in -one direction.' but that it cannot be rotated in the other direction without rotating the ring o, due to the registry of the ratchet aortions m with the teeth n. It will, there ore, be seen that when the hammer portion oscillates it will be given an intermittent rotation, one impulse being received at each downward stroke of the 'hammer portion.

As shown in Fig. 7, the rings o and q are given regularly toothed faces which are pressed one against the other by the coil spring r. The ring g is rigidly secured with in the tube l) while the ring o is rotatably mounted within such tube, the object of this being to allow slight rotation of the ring o when the hammerportion iirst starts upon its downward stroke, so that the strain upon the teeth n will not be too great or, in case the drill becomes lodged in the hole which is being drilled, to allow all of the rotation to be taken up by the .ring o instead of by the hammer portion and the drill. When the ring o is thus rotated, the toothed vportions slide upon the similar portions of the ring q, and, due to the inclined plane construction of such teeth, the spring r is slightly compressed. The rings may return to their original position after thevfirst shock or they may be relatively rotated-one or more teeth-if the resistance to rot-ation of the drill is very great. j

This drill may belsecured to a support, such as a tripod orcolulnn, by the-conical the external casing t. vWhen the drill is thps supported, it is desirable to feed the Sallie up and down, and to provide ready and col`r`V casing. The wheel t in firm connectlon,

venient means for this, the two threaded bars u are partially embedded upon opposite sides of themain casing a in the grooves Q in such casing, the external casing t being provided with guideways w therein so that it can be moved longitudmally along the easing a but so that it cannot be rotated about such portion x is provided the threads in the with threads meshing i l lnred to the upper l with an unyielding shoulder'.

While I have described a specic form of my invention, I do not wish to .be undul limited thereto, it being possibleito substitute different forms for 'many ofD the parts here shown without departing from the spirit of scope of my invention.

I claim: -y y 1. In a drill of the class described, the combination of an inclosing chamber, a hammer vreciprocatingly and rotatively mounted therein, a'rifled nut carried on auch` hammer, a rifled bar extending'into the nut, ratchet teeth carried upon such bar, a ratchet ring adapted to be engaged by the ratchet teeth,

S ring r is adapted also to receive thel Aasag'ieo a second ring rigidly secured Within the inclosing chamber and having a toothed face against which a similarly toothed face of the ratchet rin engages, means for yieldingl holding suc rin s in engagement one w1t the other, where y the ratchet ring is permitted to rotate Within the inclosing chamber by overcoming such yielding means, and means whereby the bar is permitted to rotate in one direction within the ratchet ring and whereby it is prevented from rotating in the other direction within the ring.

2. In a drill of the class described, the combination of an inclosing chamber, a hammer reciprocatingly and rotatively mounted therein, a ratchet ring with its center on the axis of the chamber, a coacting pawl having a riied connection with the hammer, and a ixed ring engaging the ratchet ring over an uneven surface. A

3. In 'a drill of the class described, `the combination of a frame/a hammer reciprocatingly and rotatively' mounted in the frame, a ratchet and pawl mechanism havin its center in the axis of the hammer, a rie connection between the hammerl and one member of the ratchet and pawl mechanism, and a connection through an uneven slidin l contact surface between the other member o the ratchet and pawl mechanism and the frame. l

JOHN- F. MITCHELL.

Witnesses:

WM. W. BOLLARD, S. O. N EsBAUM. 

